The INT-8985 has two
primary data paths: the Encoder and the Decoder. These two paths are
completely independent, and may be used to simultaneously process two
The Encoder subsystem is
comprised of four major elements. These are the input formatter, feed-thru
scrambler, look up table, and the differential encoder. The input
formatter accepts the data signal that is to be encoded from the external
connector. The data signal may be either a serial bit stream, or parallel
symbol stream. Serial data may be converted to parallel symbols, or
parallel symbols may be converted to serial data by the input formatter.
The required data format is selected and applied to the feed-thru
scrambler. Scrambling is used in the digital modulation process to produce
quasi-random, yet recoverable, data for transmission. The user may select
any combination of up to 24 feedback taps for each of the eight input
rails. Furthermore the user may cross connect scrambler taps for the first
four inputs. The scrambled data is applied to a programmable look up table
to map the input bits to symbols. These are applied to a differential
encoder and output to the external connector.
The Decoder subsystem is
also comprised of four major elements. These are the differential decoder,
the look up table, the descrambler, and the output formatter. Their
functions are the inverse of the encoder subsystem elements described
The INT-8985 is enclosed
in a full width 3U (5.25” high) rack mount chassis.